Splicing a radar cable - how difficult?

mike-m · 24 November 2009, 18:16

Have just bought a second hand Furuno radar set, a 1621 mark 2 with LCD screen. Unfortunately, the cable to the radome was cut while the set was being removed. Is it a major job to splice these cables?

It has a very fine coaxial cable inside the wiring bundle and I have been advised to join this with a TNC connector as they are the smallest and therefore neatest. Does anyone in Northern Ireland know where I can pick one of these TNC connectors up? Maplins and other electronics/aerial shops don't seem to have them....

Or would I be better just handing it over to a specialist??!! Any suggestions from the Norn Iron brigade?

Many thanks....

Mike

Channel Ribs · 24 November 2009, 18:33

Quote:

Originally Posted by mike-m

Unfortunately, the cable to the radome was cut while the set was being removed.

In my humble experience you sir are buggered.

It is possible to join RADAR cable, but you will I think do well to get hold of an all new one. Hopefully the price you paid reflected the lack of a good cable?

JABS · 24 November 2009, 20:03

You can buy all sorts of connectors from RS Components, online.

Use solder and adhesive lined heat shrink. There is no reason why it shouldn't work. Hopefully, he cut it at a point where the join will be indoors.

It will be a long job. Plan it carefully otherwise the bundle will get very thick!

Good luck!

Might be worth a trial run on some cable that doesn't matter.

codprawn · 24 November 2009, 21:45

Not done it on RADAR but I have spliced plenty of microwave links and satellite cables in my time.

They say you have to have expensive connectors and it is a hard job but I found just twisting the wires together did the job - if you want to be posh you can even solder them!!! I used kitcat foil for the shielding........

biffer · 25 November 2009, 09:30

before you do anything have a word with geoffs on here, what he doesn't know about electronics i could write on my finger nail

geoffs · 25 November 2009, 19:23

If you solder and heatshrink all the wires, making sure you connect both the inner and outer of the screened cables then overwrap the lot with self amalgamating tape then you should be fine.

No need for a connector unless you want to be able to remove the scanner regularly.

mike-m · 26 November 2009, 00:10

Thanks everyone,

Will give it a go - must admit it is only the coax screened cable that worries me. Guess you just twist the centre wire together, solder and insulate, then crimp the screening and insulate?

Will let you know how I get on....

Regards

Mike

jwalker · 26 November 2009, 11:54

Mike, before you start do a search. Joining screened cable and splicing radar lead has been covered before in reasonable detail.

GJ0KYZ · 26 November 2009, 17:55

Radar operates at a ultra high radio frequency. This means that poor cable connections are very 'lossy' in terms of transmitted and received signal strength. One short circuit by way of a braid filiment touching the inner coax conductor will push your voltage standing wave ratio off the scale and may well damage the set beyond repair. You can try BNC connectors if you want (buy them from Waters and Stanton -01702 206835) but they're tricky to put on and if not done properly you will suffer signal degradation. My advice would be to return the set to the factory and get the job done professionally.

ashbypower · 26 November 2009, 18:05

Quote:

Originally Posted by GJ0KYZ

Radar operates at a ultra high radio frequency. This means that poor cable connections are very 'lossy' in terms of transmitted and received signal strength. One short circuit by way of a braid filiment touching the inner coax conductor will push your voltage standing wave ratio off the scale and may well damage the set beyond repair. You can try BNC connectors if you want (buy them from Waters and Stanton -01702 206835) but they're tricky to put on and if not done properly you will suffer signal degradation. My advice would be to return the set to the factory and get the job done professionally.

I agree fully with what you say, however not 100% certain but I think you'll find the UHF is confined to the scanner head and the coax being discussed carries a lower frequency/power signal.

G6YUX

GJ0KYZ · 26 November 2009, 18:26

Quote:

Originally Posted by ashbypower

I agree fully with what you say, however not 100% certain but I think you'll find the UHF is confined to the scanner head and the coax being discussed carries a lower frequency/power signal.

G6YUX

Yes, thinking about it that would make sense given the long runs typically involved in yacht installations and the relatively poor quality coax described above. Thanks for that.

73 de Paul.

Channel Ribs · 26 November 2009, 19:01

Quote:

Originally Posted by GJ0KYZ

My advice would be to return the set to the factory and get the job done professionally.

My advice stands, all that is needed is a replacement cable.

Yes, you can spend hours (it will be hours) joining and wrapping each one.

Yes, you can buy connectors to make it a bit smarter.

Yes! Either of those might just end up being a waste of time/money and possibly just ruin the set.

Email John at JG Tech, he will be able to get you a brand new uncut cable for about 100 squids. Job done.

biffer · 27 November 2009, 07:37

Quote:

Originally Posted by geoffs

If you solder and heatshrink all the wires, making sure you connect both the inner and outer of the screened cables then overwrap the lot with self amalgamating tape then you should be fine.

No need for a connector unless you want to be able to remove the scanner regularly.

hello mate, you can lead a horse to water, eh!. where's my fridge bit and don't forget that welder i want you to look at, hope your'e dads on the mend, biff

Eugene Wixted · 27 November 2009, 11:17

Might be worth your while contacting Barry Electronics, St. Catherines Road, Killybegs, Co. Donegal. They are Furuno agents and mainly serve the fishing industry. I am sure they have come across radar cable repairs frequently.

Dirk Diggler · 27 November 2009, 14:34

Quote:

Originally Posted by malthouse

Yes, you can spend hours (it will be hours) joining and wrapping each one.

Email John at JG Tech, he will be able to get you a brand new uncut cable for about 100 squids.

Well, I don't know about you, hours of my spare time is still favourable to spending £100 on a bit of cable!!!

Channel Ribs · 27 November 2009, 14:39

Quote:

Originally Posted by Dirk Diggler

Well, I don't know about you, hours of my spare time is still favourable to spending £100 on a bit of cable!!!

I do know about me, I would charge 100 quid for the joining process!

But when it comes to advice and someone doing a complicated and delicate job like this for the first and possibly only time I would think a safe 100 quid was better than half a day gambled. RADAR is fairly important after all, imagine it working for a few months - just long enough to get used to it and rely on it - then paff.

Dirk Diggler · 27 November 2009, 14:50

Quote:

Originally Posted by malthouse

I do know about me, I would charge 100 quid for the joining process!

But when it comes to advice and someone doing a complicated and delicate job like this for the first and possibly only time I would think a safe 100 quid was better than half a day gambled. RADAR is fairly important after all, imagine it working for a few months - just long enough to get used to it and rely on it - then paff.

Unfortunately, that is the Marine trade in a nutshell.

Over complicating a very simple job, and making it souns like it could all end in tears, or possibly a dangerous situation if done incorrectly!

Simple soldering and heat shrinking is a peace of pee, your daughter could do it after a couple of minutes tuition.

Channel Ribs · 27 November 2009, 15:26

Quote:

Originally Posted by Dirk Diggler

Unfortunately, that is the Marine trade in a nutshell.

If a marine trader does not explain the possible complications and cross the Ts, if it all goes wrong the paying customer has a right to expect something to be done about it.

It is important to make sure the customer understands the risks associated with patching up versus replacing with new.

I am sure the OP will make a decision about which way he wants to go, having been given all of the options....

An easy repair that cannot possibly go wrong, rather than lining the pockets of an evil marine trader.

or

A straight forward purchase of a new part with all of the usual guarantees, rather than a possibly unreliable and fiddly chore.

I know which I would go for and clearly so do you, but lets try not to be too critical of the other approach?

Please also bear in mind that I had a nice cheeky smiley when I said I would charge a hundred quid.

Erin · 27 November 2009, 16:06

If you want my 2p's worth:-

If you've soldered before, and know what you're doing, then go ahead and splice it together. I've soldered countless wires together over the years, and reckon I could do a 10 core cable in under an hour. I'd be very tempted to use a BNC or similar on anything co-ax mind. The signal frequency in the cable can't be that stupendous seeing as it relies on pretty basic plug-in connections on the back of the display.

If you've never soldered before..... now is not the time to learn.

Anyway, I'd do it for £90

Hightower · 27 November 2009, 16:18

Yeh, I'd have a go at the splicing and soldering route too.